Question 703514
Plane  	speed	=x	mph					
wind   	speed	=y	mph					
against 	wind   	5	hours					
with 	wind   	4	hours					
								
Distance with	wind   	4800	miles		distance against	wind   	4800	
t=d/r	against	wind   	(x-y)					
4800.00	/	(	x	-	y	)=	5.00	
								
5.00	x	-	-5.00	y	=	4800.00	....................1	
with	wind   	(x+y)						
4800.00	/	(	x	+	y	)=	4.00	
4.00	(	x	+	y	)	=	4800.00	
4.00	x	+	4.00	y	=	4800.00	...............2	
Multiply (1) by	4.00							
Multiply (2) by	5.00							
we get	2.00							
20.00	x	+	-20.00	y	=	19200.00		
20.00	x	+	20.00	y	=	24000.00		
40.00	x	=	43200.00					
/	40.00							
x	=	1080	mph					
								
plug value of x in (1)				y				
5	x		-5	y	=	4800		
5400			-5	-5400	=	4800		
-5	y	=	4800					
-5	y	=	-600	mph				
	y	=	120					
Plane  	1080	mph						
wind   	120	mph						
								
CHECK								
x+y=	1200							
X-y=	960			+				
4800.00	/	(	1200.00			)=	4	
4800	/	(	960	)		=	5